Curtain Call
by mabel-but-slytherin
Summary: Bill Cipher wasn't sure where to begin with his plans to free Lucifer, until he found the perfect stage in Gravity Falls and the perfect puppet in one of the special children who lived there.
1. Chapter 1

**AN: Hey everyone! This is my first time posting a sequel for this story, as it follows the events and theories laid out in Afterlife (despite the fandom change). This story should be understandable on its own, the main idea that carries over is that Azazel from Supernatural is Bill from Gravity Falls, but if you want to see how that came to be feel free to check it out in the Supernatural/Danny Phantom crossover section.**

**It should be said that this story takes place from the Season 1 finale of Gravity Falls through Sock Opera, as well as after the beginning of Season 6 of Supernatural, and will contain spoilers up until those points.**

**Enjoy!**

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Pine Tree and Shooting Star may have managed to kick Bill out of Dipper's body, but that didn't mean they could stop him from watching over what was _his_.

Bill knew since he found the children in Gravity Falls that they were the ones he was looking for. Just as it had been with Sammy when he originally made the deal with Mary Winchester, there was a certain spark in the Pines twins that drew him to them.

With Sammy it had been the bloodline. Bill only realized after the fact that he had failed to see the warning signs in his attraction to Mary Winchester, the demon had been as drawn to the mother as he ever been to picking her son as his favorite, and cursed his old self for not seeing the bigger picture that existed beyond the schemes of his grandiose plans; plans that seemed all too pitiful when compared to the history of the world. The script that Heaven had written in prophecy had been laid out perfectly: a hunter mother longing to escape the family business, only to be pulled into a deal killing her and leaving her husband and sons, innocent vessels all too unaware of their heritage, to save people, hunt things, and eventually choose the fate of the Earth. All too naively Azazel had followed along, playing his role and unwittingly resigning himself to be the puppet of the very angels who betrayed him and the Morningstar, who believed they had the right to choose who was slave and who was master, who could be redeemed and who was damned to Hell.

The error in his ways made Bill sick. From now on he swore he would be the puppet-master rather than the marionette.

And getting to control his own little puppet had felt so _good_, the magnificent feeling that came with the freedom of having a physical vessel, of getting to be truly alive rather than dead in the Mindscape he hid in after so long was only compounded by the fresh _power_ flowing through Pine Tree's veins.

Sadly the demon could no longer manipulate his form into that which was required to invade a vessel effortlessly, to just waltz into a meatsuit and throw it away without a care when he was done. He regretting not being able to simply inhabit an unimportant resident of Gravity Falls in order to watch and manipulate the twins in person.

Dipper and Mabel Pines were probably the only two people in Gravity Falls he could possess.

They were two of his special children after all.

While Sammy's bloodline was what first caused him to stand out, Bill had originally noted the Pines when he arrived at their doorstep looking for one child to feed with his blood only to delightfully find that their mother had given him twins. It wasn't the first time this had occurred: Andy and especially Ansem had been playing out to be strong runner ups to Sammy's spot as Azazel's favorite at the time.

Still, the demon couldn't help but smirk when Mrs. Pines made the smart decision to roll over and go back to sleep rather than disturb him. He had big plans for how he would play with the older twins' separation in manipulating them to his cause when they came of age and their powers started coming in, but he was especially looking forward to watching how twins would react to gaining powers _together_.

Both Azazel and Bill had fully intended to wait until the pair had begun developing their abilities before visiting them again. They were a curiosity, but the entertainment that the dream demon derived from them would be in watching their normal lives shatter; it didn't do him any good to spoil the show now.

After all, they weren't the most likely candidates for the leader he needed. There could only be one in the end. No, back when Azazel was making his plans it seemed much more amusing to let them grow closer and rely on each other and then see if either of them could rise from the ashes at the end to become anything more than a particularly amusing tragedy.

Only when Bill remembered them had he realized how much his plans had changed.

Watching the apocalypse go up in flames had a funny way of doing that. On one hand Bill was secretly glad that everything didn't go as planned. Watching from the sidelines (with a head occasionally reading over the shoulder of the prophet writing the play-by-plays only adding to his cynicism) it was dreadfully obvious to the dream demon how the side he had worked so hard for was clearly never meant to win.

But hey, if God made it that easy to successfully rebel and snatch the world away from Him everyone would be doing it.

On the other hand Bill was furious with where he went wrong with Sammy.

It was clear that the boy simply wasn't deserving of his role as Lucifer's vessel. The bloodlines may have been perfect, the script may have had appropriate amounts of drama and heartbreak to make even Bill shed an (albeit sarcastic) tear, but all of the experience Azazel prided cornering the boy into simply created a Sam who was far too resilient to give in to the Devil. Perhaps that's what Heaven had planned all along.

The Boy King had always run from the supernatural to a life of simplicity, but Azazel had been wrong to label the disapproving familiarity and skill Sammy had with hunting to imply that he would be willing to betray everything he held dear when the time came. In the end both brothers had been far too desiring to cling onto any sense of normalcy to ever bring about the apocalypse, they would delay it for as long as they could, which given their roles meant indefinitely, even if it meant being relentlessly hunted without a shred of hope in the name of Free Will.

For the first time Bill truly realized that Lucifer was always meant to be a snake, not a soldier, and his vessel should reflect the master. Making the spectacle of Cold Oak to kill his special children at war meant nothing when he could just string one of them along until the seals were broken and his Fallen Star was ready to take center stage.

Bill wasn't going to make the same mistake twice.

The dream demon began his hunt for the next vessel as soon as the smoke from the final battle cleared, screening the talent pool in search of promise. The next generation was about eleven years younger than the first, as Azazel had begun making fresh deals as soon as he finished marking the children of his first, and while a few had disappointingly minor supernatural encounters, none were near developing their powers. They were ten years away from being discernable in terms of magical ability, but there was no reason the dream demon couldn't take an elite few under his wing, train them as he had his previous finalists. The key was simply not getting too attached to a favorite, and if there was anything Bill had improved in his death it was twisting nightmares without tying himself to the mind he manipulated.

He was steadily making his way west towards the California coast when he felt an unwelcome lurch pull him across the finish line.

The last time the demon had been summoned was by one John Winchester. It wasn't just that the lore surrounding the former King of Hell was buried deep (even the attention the title should have garnered was eclipsed by Lilith's shadow, just as Azazel always preferred it), it was also that no demonologist in their right mind who had stumbled upon the information would ever _dream_ of summoning him when there were dozens of crossroads demons willing to do a human's dirty work for a far more agreeable price than he would ever offer.

Bill Cipher was angered by the summons, and when he realized that he was too far gone from his old life to masquerade as Azazel he prepared to go all out with the show in his new form. Might as well have a little fun before killing the fool who decided to mess with him, after all.

That's when the demon truly heard the summons that was echoing all through his being, and his eye opened to see a beat up leather journal in the hands of his summoner (a kid, he noted with a glimmer of amusement, that should be fun) containing information that for all intents and purposes _should not exist_.

It appears that Gideon Gleeful (skimming the name of someone so prideful off of the kid's thoughts was child's play, pun intended) had intended to summon Bill Cipher all along. Things were about to get interesting.

The demon looked around as he slowly made his way into existence. The summons was enough to allow him to meld into reality better than he had in months: the further he voyaged into this world the harder it was to interact with it beyond the carefully strung web of the Mindscape his powers made. If information about his new form had leaked out, Bill needed to be careful in controlling it and hunting it down, and knowing about his surroundings was sadly the best he could do at the time.

"Gravity Falls, it's good to be back!" As the dream demon committed the name to memory even his near omniscience failed to realize how significant this town and its residents would become.

If he was going to write a new script after those annoying Winchesters threw God's out, he would need a stage.

Bill had no intentions on going along with Gideon's plans. After all, while the demon was still racing to outline his own machinations and discover the mysteries that made up his new chessboard, he was not a minion to be bid and the young psychic was clearly not a piece of significant value. It was far too easy to rattle the child with insane parlor tricks as the triangle let his aura wander, not even paying attention until his hearing perked at the familiar name of Stanford Pines. He was busy trying to remember where he had heard the name Pines before when he felt the familiar glow of one of _his_ children watching nearby, its twin star obviously not too far behind.

Bill couldn't help but rub his hands as everything all too easily clicked together. It was far too perfect to be mere coincidence, and yet the small backwards town was obviously too remote to be on anyone's radar with all the drama and civil war breaking out above. He would have to find out who wrote the journals later on and insure that they came to be.

How lucky was he that time never moved perfectly straight in the world of his newfound death? He was going to thank himself later, or more accurately, thirty years earlier.

But for now, he had a deal. He would get closer to his new favorite children, obverse their guardian from the inside and begin pulling the strings and laying the foundations to mold the perfect soldiers that Sammy never was. Who knows, with him on the other end of the timeline, maybe he had thought forwards enough to insure the knowledge landed in his special twins' hands to ensure they followed him in to their Grunkle's mind so that they could meet face to face.

And this wasn't even taking into account the reward of firsthand assistance through a new puppet with access to the journals Bill would eventually have to frame.

It was good to be back in the game.

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Watching the Pines twins chalked up to be everything Bill Cipher could dream of and more. They were disgustingly adorable yet creative, imaginative, and powerful. Watching Shooting Star fire kitten cannons out of her hands as an initial reaction to the freedoms of the Mindscape made Bill cackle in anticipation of how wonderful it will be when his gifts to the kids finally kick in.

Mabel Pines, however, didn't hold a candle to how perfectly her brother fit into Bill's plans.

The boy was smart, and while not as creative or powerful with the realm of the Dreamscape as his sister, his determination and focus on a task would ultimately make his a stronger soldier. The demon had been planning ways to train the boy in these aspects, giddy with the outlook of the physical and especially the moral guidance Stanford Pines was already beginning to impart on the boy, when he witnessed Dipper read a spell to raise the dead all throughout Gravity Falls and nearly kill them all.

Never before had Bill Cipher or Azazel been both so panicked and so proud.

He was a fast learner, an avid hunter, and never failed to get his nose in too deep, all qualities that Bill could foresee manipulating (and simultaneously watch play out) as the boy devoutly followed the words of the demon's scribe in hunting down every riddle and cipher in his journal. While Sammy had been admired for learning to face the supernatural while eagerly trying to get away, Dipper dove headfirst deeper and deeper into the darkening world around him. If anything, the boy was already shoving aside humanity in favor of a new unknown.

And while Azazel had previously grown kids into murdering psychopaths, Dipper Pines, dare Bill say it, had the perfectly morality (or lack of) to suit the job. He would stop at nothing one day to protect his sister, leaving the perfect bargaining chip already in her blood when Bill needed it, but would completely ignore her to follow the trail of breadcrumbs Bill laid out with the laptop the next. He would raise the dead, he would put his friends in danger rather than come clean to them, he would cheat, he already hated the hierarchy of existing society, and all within the first week of Bill silently following him along, not having yet even raised a hand in fear his touch would taint perfection.

The temptation to play with it was unbearable.

So as the boy was playing with the laptop, obsessively discussing how what the author hid in his paranoia must have even more secrets than all of the journals, as Bill for the first time since his death was clenched with the bone-chilling _fear_ that perhaps there was a way this could get out of this control, after all, _he hadn't even gone back to set the stage and see for himself yet_, the dream demon saw a power play in front of him and decided to go all in and play his hand.

It was pitifully easy to string the boy along, and even now the power the laptop and the author's secrets were gaining too much of a hold on his special child's life when the demon wanted, _needed_ this one to stay under his thumb and play his role. He had planned to crack the code to the laptop within the boy, to shield his mind and memories from its secrets as the demon had a firsthand look at his guiding star for the first time since coming here, maybe even keep it himself when he was done, for future reading and bait.

Dipper once again managed to throw Bill Cipher off of his game. There was no way the demon could've expected the sheer power and destruction that roiled inside him as soon as he came into contact with the boy's flesh and blood.

It felt as though Bill had just come back to life without ever realizing he'd been dead, though in a way Bill supposed that's exactly what had happened. Every movement, every sensation, every _heartbeat_ sent more of the boy's blood, of the _demon's blood_ pumping through his every cell. Even his demonic tendencies were heightened, and next thing he knew the laptop was smashed beyond recognition, the creature that once was of careful thought and planning but was now caught in the moment found himself stumbling along searching for something else to wreck.

Like his well-laid plans.

It was a testament to how far gone Bill was that he was willing to scratch, let alone batter and break a puppet that was so crucial to the fate of his world, but isn't that what any newborn does when playing with their toys for the first time? He was smart enough to keep the boy alive, which is far more than what most human hosts can say when faced with a gleeful demon possessing their bodies.

After all, the vessel's pain was a strange brand of white-hot sensation and unbridled freedom the demon could only describe as hilarious.

If the demon blood Azazel had given Pine Tree when he was a newborn felt good coursing around on the inside, then freeing it, watching it pool and paint across his skin, bathing himself in the essence was heavenly.

But just like anything even remotely tied to that place, it was a trap that the demon should've known better than to fall into.

Bill Cipher was lucky that Mabel came around at just the last minute to push him away from destroying the third journal entirely. She was almost like a twisted Dean in a way to fit his newfound Sam, willing to do anything to stop him and protect her brother (even when it only furthered the demon's plans), yet unlike the infuriating Winchester who didn't know when to give up, Shooting Star seemed so easily distracted Bill could hardly imagine her becoming a threat.

That didn't mean she wasn't largely included in the eye he was keeping on the twins. And if she ever did mess up, he had a _special_ card up his sleeve he never had when it came to the older Winchester.

The demon's logic, twisted as it was inside Dipper's shell, had argued for destroying the book in order to prevent the child from finding potentially major answers that Bill might not have accounted for. After all, leaving the boy to chase him for revenge had worked before in the past, both with Dipper and the many puppet's Azazel had claimed before him. Yet the old habits that lingered in Azazel's blood died quickly as he flew out of the boy's body and back into his triangular form, and he realized that despite the epic failure on everyone's account that had gone down at the opera, there still were enough loose ends to be strung perfectly together.

After all, if Dipper didn't trust Bill and Bill vowed to destroy the journals, surely the boy would dive into them even more? Only this time with the lens of his vengeance leaving him wide open for the perfect shove of reverse psychology to augment the journal's pull.

And when push comes to shove, Dipper was destined to be Bill's puppet, in a bond formed this time by Bill's own flaming hands rather than by Heaven's design. Today was but a small stumble that opened many new doors, and as long as the demon kept a level head and bided his time everything would play out perfectly when the seals reopened and the curtain rose again.

Everything was in position: the stage was set, the script was rewritten, and the puppets were just dancing around waiting for their cues.

After all, _yes_ was just a simple, one-word string.

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**AN: a quick note about this story. It will have a sequel that will be a three-shot, but because I have a problem with bouncing around idea to idea I'll likely wait until the first two chapters are written before posting. I'll leave a quick author's note here as a second chapter when the beginning's posted, though it will remain in the Superfalls fandom if you want to find it that way.**


	2. Sequel is posted!

Hey, sorry for the long wait but this is just to let anyone who's still waiting know that chapter one of the sequel and finale, Encore, has now been posted!

Thanks for sticking with this all this time!


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